Separation of petroleum-oil sludges



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-' grovement in Separation of Petroleum-Oil ludges, of which thefollowing is a specification.

This inventionrelates to the art of refining petroleum oils and ispart1cularly directed to the treatment-of the acid sludge resulting fromthey agitation of such oils with sulphuric acid. The invention W111 befully understood from the following specification.

In the manufacture of lubricants from petroleum oil, for example,American mid-con- -tinent crude petroleum, the/crude oil is subjected todistillation with fire and steam down to a bottom of 80 to 85 er cent,that-1s, until to or cent of t e oil has been distilled bfi. he steamreduced'crude resulting from this first operation is now agitated withfrom one-third of one pound to one pound per gallon of sulphuric acid 66B. As the result of such acid treatment there is produced a sludge whichseparates from the oil body drawn from the acid agitator. The presentinvention is partlcularly directed to the treatmentof such acid sludge.

The sludge is pumped into an agitator where it mixes with water (10% onthe mass of sludge), or weak sulphunc acid, that is, acid of a gravityless than 8 B. (15% on the mass of sludge), gas oil, and a product whichis identified as fuming acid sludge. The gas oil referred to is amixture of heavy petroleum oils having a boilin point of approximatelyfrom 500 to 700 and is used in the proportion of about 20 to 50 per centon the mass of the sludge to be treated. The fuming acid sludge re erredto is produced by the action of relatively large quantities of -fumingsulphuric acid upon heavy petroleum ,oils of the character used formedicinal urposes under the name of White oil or iq uid parafiine, asproduced, for example by the recess described in the patent of IlobertHumphreys, No. 1,286,179, of November 26 1918. It is preferred thatprior to its use in the present process, the fuming acid sludge referredto should have separated from it the bulk of sulphuric acid which itcontains. This may be readily accomplished by the addition of water tothe sludge the thorough boiling of the mixture and settling.

character.

Specification of Letters Intent. Pat nt d J e 9 Application. filedDecember 28, 1918. Serial No. 268,071. j

' As the result of this treatment, the sulphuric acid content of thesludge in large part comes out in dilute aqueous solution (about 15 B.)in the base of the settling tank, the stratification being relativel.perfect. The fuming acid sludge obtaine and treated in the man ner abovedescribed is used in the present process to the extent of from 5 to 35per cent on the mass of the oil sludge under treatment.

'The mixture of oil sludge, fuming acid sludge, gas oil and water orweak acid having been made as above described, is now steamed until itis nearly at the boiling temperature. The sulphurlc acid contained inthe sludge will now in large part separate out at the bottom of the tankin the form of about 30 B. acid. This 30 acid is now drawn 016', morewater or weak, acid added and the mixture again steamed, after whichthere is a second Stratification and a further quantity of acid of agravity less than 30 B. may be drawn ofi'. This process may be repeateduntil the ga'avity of the acid recovered is from 8'to 10 beyond whichstage it is 80 unnecessaryto proceed.

The product now remaining in the separator forms two layers. The upperlayer which is called tar consists of a solution of asphaltines in gasoil. The lower layer consists of asphaltic products and mineral oilsulphonic acids, and contains in addition from20 to30 per cent of weaksulphuric acid (about 9 B.), together with small quantities of oil. Boththe upper and lower layers are suitable for the production of commercialasphalt, the best results being secured by drawing them ofi separatelyand treating each layer by the method best suitedto its 85 In the use ofthe above described process for the treatment 'of sludge, it should benoted that the proportion of fumin acid sludge emplo ed withinsubstantialfi' the limits given, s ould be controlled by the followingconsiderations. The larger the percentage of fuming acid sludge emploed, the quicker the separation of the oil slu ge into the two layers,but the more difiicult the recovery of the acid therefrom, particularlthe weaker acid resulting from successive a ditions of water and steaminConversely theismaller the proportion o fuming acid sludge employed, thelonger period required for the separation. of the oil sludge, but thegreater the facility with which the last traces of acid may be removedtherefrom. The fumin acid sludge described in the foregoing as eingemployed for the sepa- -acid inthe ordinar oil sulphonic acids.

Wh1le in the foregoing there is described a particular process inaccordance with the present invention, it will'be understood this isillustrative only and that .the invention fuming acid treatment ofmineral oil, simultaneously agitating and heating the mixture, andsubsequently permitting 1t to cool and stratify: v v

4. e method of treating petroleum oil sludge for the separation thereofwhich consists in admixing with said sludge heavy petroleum oil water,and fumlng acid sludge, agitating the mixture with steam, permitting themixture to cool and stratif should not here arded as limited to theexact drawin of the resultant dilute sulphuric procedure descrlbed,except in so far as such limitations form a part of the accompanyingclaims, in which it is the intention to claim sludge for separationthereo all novelty inherent in the invention as broadly as ispermissible in view of the prior 20" art.

What is claimed is 1. The methodof treating petroleum oil sludge for theseparation thereof which consists in intimately mixing said sludge withwater and mineral oil slud e sulphonic acid of the character derived irom the fuming acid treatment of mineral oils, heating, and subseguentlypermitting the mixture to strati y.

2. The method of treating Ipetroleum oil which consists in intimatelymixing said sludge with heav etroleum ;oil, water, and mineral oil sl uge sulphonic acid of the character derived from the fuming acidtreatment of .mineral oils, heating, and subsequently permitti rllgl themixture to stratify.

3. e method of treating petroleum oil sludge for the separation'thereo'fwhich conconsists in addin acid, a ding water, and repeating theprocand-fuming acid sludge, agitating'the mixture with steam,stratifying, drawing 01! the sulphur acid layer from thebottom, I

adding a further quanti of water and re-- peating the process untll ,thebulk of the sulphuric acid has been removed.

6. The method of treating the acid sludge of steam-reduced crudepetroleum oil which thereto water, gas oil and fuming acid s udge,agitating the mixture with steam, stratifylng, drawing oil the sulphuricacid layer from the bottom, adding a further quantity of water andrepeating the process until the bulk of the sulphuric acid has beenremoved, and finally drawing 01f separately the upper and lower layersof the treated sludge.

STERLING I-i. IDIGGSI

